SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20389c7cc8fd61f90c3e577039573dd43993e17b75744242b143b075d5fb9ff4' 
  AND token = 'KGzF4wZvFUWx9jxABjwCSn7OmwV5bXp1lQLd2nCTs5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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