SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '79ef681e3059b2ee730001ed3b6f4625b6a1c741cedbc6b54a73bfaf5acf20a3' 
  AND token = 'jmBamBBFssHrMX0UrpWD28iBL3jvrigpFjDF0X22eQ8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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