SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'feeb400ced6bd1415828685372197eb1a151ddb52c16614fa2663358df497df1' 
  AND token = 'Y9O7RaMjCtutFRK4jUZjIiPZQeqm/QpakMxoP65dlQ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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