SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '015b243b87a23a9d414a9e5543053158123a62aa269678b8ebfff5d2dfddd76f' 
  AND token = 'xYT5oD9TL1Hfjv1afKmoyundakpDC5FVQmc479ZB5ns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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