SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a75d272adc70f2dcebdddb58116817f2860897d696ba60ff3f3ce3253df37025' 
  AND token = 'tBI0J/zOxpk+i8wzDkJc/IDDdmtUBI3mn3dgKs6Y5lc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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