SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56631aef0255f1a79985799af75c99b152728a8a85288990b52ea5c731a7d48f' 
  AND token = 'JclWr0kroxoGD55ZTgGOto6L2VSQROKo34Jy2r2QXP8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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