SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '758cf325f6f47de64301223bddbf37468158a4a379ab8e09ed056ba2b4b7cfe5' 
  AND token = 'gkNFUyvHN0Rm5UUfWlwPsDMeTgvM/aHnZbHgRJC28yA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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