SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '466b821843e7f141af3569f5f21989d21aad9d81c48acca38432230805cec157' 
  AND token = 'sJG2iasAggkmijHFmsfwe4oyTipBHD+NBXajqYi8l1I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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