SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1a69a17dd469732dcc53ea22ba236bcbac4375c1286299319b975c383f063225' 
  AND token = 'B+FYnfv0p9QEu6Mnzm7+mLZZxpzdZruFDvvhPfpvEvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00052

JSON explain

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