SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36f41c7478ca8002fe00add857810497bf7cad76b905d82754fc750a839965e6' 
  AND token = 'QzJICPbwNJStMwC04EIcYRyZXCioXCAx42qJeS2Zz7c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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