SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b7d295c007df0edfdd77a938bbd85a65e0fa774de56664842dc2afa261fb00d6' 
  AND token = 'LBX0WjSvqeSfQ+9jYpnjUPg0l3gJsVDuGqVAxmo0ZiA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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