SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'df50f2c956451fc8b11598f2f5e17e8376dd3be2b46430196660f2929f121656' 
  AND token = 'kezHQBmvtGmer1fTUxL9e+K117K1UwUN0eB3waAbEPk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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