SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dd0d9148f6d7a31fae35c5c778d26808486c70c933dd360974f15a6c5d031e2' 
  AND token = 'i8rK2qOOPiEYaxsrnz27fRsQBPUUCeSgV0Vq7yoOTZo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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