SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f37e9970bbf9fb51194befd9fbf9a4d5ca9ba3d4acafc5c8da9a8e258d1bb1e' 
  AND token = '6jHoCwZ9jVGBg271a1J6me/azS48Ye2kCkPgZ48V2Xw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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