SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '159e78751ed7c411cbc2b15f598f6dc16b0d304ed4efeafb466612b2c4663c8c' 
  AND token = 'sw+AfJkxaBCpPu/a7sXsZz3HKHR0kzhaKhMPKFDonLE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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