SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cf0fb39d0498b5af13baf1e8ab8d75f68cda3b475027c88df74edf4ddba69680' 
  AND token = 'ZIGE6Xwg3htJqy+aUpvCQLoHFxAyClnfB9FmOQR/lQk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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