SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f163229829a94b5203946e4101935f6179ae638543fa251d7e475bd5ef16b6c1' 
  AND token = 'JTe4XmSsxHofsqnCCSaJZXhfpiNJ+AVMA/+gGVixb44=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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