SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6a317995e163868fa9eb8d28acf406a9d016c47b59add86efaa98c4a8a5e26a' 
  AND token = 'yA1mgjG7wT2kNwmQy9tImWoFH64TAJ0P9Qsxu8L6K+g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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