SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5af6faf03b84dbe5062f937c5b0753c4d003a3a0ff02097799ace67b6283ba3a' 
  AND token = 'J49UNk+KJb7UPHM6kY+qshh5ET+p43nHu/ZIY+hR69E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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