SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ebea27247c459cddcb6c26ed93be0c2926092687018088ad989392c5b8397575' 
  AND token = 'dxj3+kpn8qve/k2/cO2du9ZSKTyLBSyUj4rn8g5+nFw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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