SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4806b236a204d130c56934bf884e71d73fe1136caa18ced0949ec1c19523d6b6' 
  AND token = 'xymEk8RwFl6KBsCVBy+JZPK5QHlYP8HCgR4Q9OFrC7s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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