SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dcbc18208962af98ae38e55ef6718ed67f31cf7aad042f324f601e57530f9c1f' 
  AND token = 'ATl7pOKAsesotd+iIfVLvzh22w/BeNKL+IRmqPvg070=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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