SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36116ca789e38415a518243380dd82757af632eb1135ea2a56c1918bc5076a50' 
  AND token = 'TkAgJwcI3Y1KBF3B5cA1dfFwp78xHdU3z4CjrN3taD0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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