SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eb9fcaa4b2cb5ebb467fb69c254b36a8589a79888e7367708f4cae0422a3eaf0' 
  AND token = '3MPZUmqVWsHl8XJBbynQ4cBeaPkU4srgV4SHOICEXsU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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