SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '991ee0530946f40f63c959345d9356c84067fa0bc42134db539179747e43a519' 
  AND token = 'mpRFYMazzbAUjs6LON/fWJvtZEdZZOCi5WV4YJlXHFE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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