SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6252b212785f2f1791fd1121cf985a92552cd9c46b7865f4e09a3e7403a9cd13' 
  AND token = 'IV/UObHYGHIh0jTbt/qdkJDPZV99J7pZ/bczEPuLJZ4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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