SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5d6c694922bafe0c8314a459cdf1c076a95ffb75fe4576998a62ed366ba23164' 
  AND token = 'DBUE7JIVUjTB4vjf+Zx7TJMTTFjzaFmgZx5EQqr8NvQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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