SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65d54c71d3a17f24bd08c9189304d272da9b964f4bcec553bed448fd32bf3a30' 
  AND token = '6S4/IfgXUwXB+Ydpge2U6S+uUg83xmSmvIqwpt0V5HQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}