SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b2c1b758f0fd7dec2c5f0ce071e7da87b154f2be624a079e39336120ff04a6b5' 
  AND token = 'H+jVk0k55yGfFN5hZOB8S5zv02Jil7B6CK9hJpVczwI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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