SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5dc68170340ea7c6069a155f2c32ae919aed7b8a4d641bc32244f1d8895f652' 
  AND token = 'BG2oALFVTv1P8ZxR/AWaYeNrRtJKbwBzb/Dl/Hs7EeQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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