SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd679878851222fd0d9bbf914647a240d9a87f6d8b5fce3d91a638af123171443' 
  AND token = 'eOJyzji6HbvxP/Mm7VFh9jirfDGSbP5v5XLZC8ixSZE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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