SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '59bcbe53bfd6a52936f8f1ee327c201b2d30068de22cbe758ed40063397749a6' 
  AND token = 'txVcoZ0Y8hB0rk3rFbBdNb2iy+KYd6kO5VpPPCak5PU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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