SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '561230a6c8548d37993081a5fd4610a302ed420753de2575099b12691231aadf' 
  AND token = 'l3x1MxHOJ5sXpfWXoaq+1y40D+oSFXDXYwBHfOfqNfc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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