SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70fc4c3108d06a2843e864e534e673ef4c00cc690b8c8986a0e50a1a8fd8a513' 
  AND token = 'kBfz2yNC+x4IYvO1pXwXTkjC7dNGFaUcSAko7K9f4ls=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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