SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cde6f47b99ca9cb09761aa44f668349a0b3f7e8a11ccc1183208636efbb37d81' 
  AND token = 'HzOlrTeRTtrqSXMJPLFd6fwi7faeu31Lg2oALkvhvGw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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