SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'f1d2bfeb17190b9deb369e48a36269ab3261cb85d394081a3daa75cf61587853' 
  AND token = 'B8qxk74/uUxXPb0YJFosbSG5nt4TJrLLp+lGYxEJk2k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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