SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f55d1b276457e14d71eaf2f7f86f689d0f14d7b0790afe89b8e4237fe659585a' 
  AND token = 'Wj8EQoxZhoVRXrdubTJ50hOw5Oa+ffPXuwyZkyfPorI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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