SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '720e0c8e27b49915e0ead6dba846efb51ab108b85a2ed7a480650bfb234d2692' 
  AND token = 'b5l6Qc/6sAUqKkDJ3z0fqYtUoyI+aEcEXAps3cNYeps=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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