SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8941a79c7922eeb58795e803c1745a1042268b9cb631cab20abe8598072751de' 
  AND token = 'cmpbmj+6gj51pr5Yw/W87QUmuOvLZc6/D2HWpXRuml0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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