SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '828447936d37bcbef5bca6af427c46baf1bd06eb541b78563aa7738dd1bbdf83' 
  AND token = 'lpmgQwGtT7SJWwJK9o76Vx9nh9B0ka5LJ8FvLA/IrK0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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