SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '694eb8d3fc17d7c870de095abf2c2cff394a8898aa377f31f34349759ba29469' 
  AND token = 'K+hvP3D89OLNKxTjTMg/VPObqAik6u8Zvgf4Fm10cEs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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