SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac87b9fb7a821e988b26927f59963a0584955ba0691e5f516d88de107728765e' 
  AND token = 'YQ3GqQa7bZJfqC9upSUnoLLTOZ+PiYCs/CzEo9B3glk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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