SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18db93d26ba83329390ff7d306243fef9b911833678dc35f51da2afaad28e988' 
  AND token = '/JCktN7YJJogMaf0txQjBuHEDqLIj53FhBftrWDa/W4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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