SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18825985ac25a8a03e58cf83d957ad56cd093681914424744e4587229aca7123' 
  AND token = 'LE3VPzRDSgKfeXgBp9L53wMtg2SaGjxjGYm/Et57eKg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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