SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4261144f10a6be6b5007ed81ab0bc17301e38610c374249f6bb63bd83e5f216c' 
  AND token = 'RWTqad3v+HbIbgDgs6I+uys2POqvzcLnWCTZtixJGSw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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