SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7dff304f86e68b13e41ce5a750b18421db3cbe433032fe47c450bfed6a3f43af' 
  AND token = 'C0xRUCPrd93SLeXJRbv7qZpEFxCCGwnMD7chkZrO1wc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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