SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '266df0f45882857b1b5f9d01f5ee64fcdddf5cba2c50553fb986644b058756f2' 
  AND token = 'c+06G7scZm1n15X7yLF/iA1Bg4Ju0hpke0wwsPlekeY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}