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SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a6808b5ff9d3d9e636486267fac0352db1d00e9a64bb27d21d5ee6b4c5fc2652' 
  AND token = 'X6WjwHR9Lp6y4n8qcF89n2JRz3m12aK1cGgV+FIAWx8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}