SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '978b432070ad5a2d5962696325f80a6d3940f2aa61c9cd02d35d57223b4c5e9a' 
  AND token = 'g9hzL+dMHodpe0ypko8wuP6qS4oPPxfM1J8v/5/vIUg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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