SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a06d6d354a2f4904c7ae40493c823276be516fea6881e16070eea493273392f' 
  AND token = 'LPukoPZqxSD1y2dUCDCgoZatuXDdan9+ITxnHxT4aAQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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