SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ceaa8363b1dad4e3214b091b53738b6592838b76568c7b7c50a0b2ac0bf88555' 
  AND token = 'nJ/27SxFmbEwf4xhS0haUtN1+jsTKLGVKgHz0P4LvZM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00015

JSON explain

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