SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac037ef5e77fbe30f1f33a42147c29ec95add718d1db8add1e5f72a681f3ef09' 
  AND token = 'JKxHK56dpNUVV4smpB0pN8Q3gsvyR44fv2wu/gEIztU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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