SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '35712a1d49c2bc06fe166070d9347fec3335af01155a7312bcc122d90adf6961' 
  AND token = 'xfLUoJJBwBdBo8gbWTgsEtJ22kSTl9K2mMFbgo6NjsI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}