SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5a366873342f3c8a2e15379e55ebf3ba877e8c1c4a9012cd98c173648381c8d' 
  AND token = 'pEC+u+ytfRK5OdF1vf8qqYKPYzWdVo1/xKwIDL1NYhU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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