SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '442e6f838aab10316a17a457e4654454b3cb0889183fd2f9bee299c675c82042' 
  AND token = '1Yh7veaXXm8dYufhYLerJn1An7zziLJhTflPSN7pbA4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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