SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e39a0188897097b3f55b9691f073d7d743579f2e4c526c5366cac36edfb6b4d' 
  AND token = 'TIF1s0DF/1avZ59QrSgK1mjPJ4nK63dDVMshLuj5GWc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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