SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8f8e774eac59826b1b194cbce609592aa644e4390ce3e153f44b274cf32e42b5' 
  AND token = 'SaAeC37ld48wfaMT5vOAZEKvCfJFzE5ZtsxnFk7k2XU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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