SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '855622cc931dac6aa59a30d894d2b49db5f97d0ca4f33b3ab7e981035dc5952e' 
  AND token = 'yLh4JER4rXwxA3D14hC2mSIMP+FFCRJqzBxL/LruWOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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