SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5af5fadae9baa5a454298a330c612dc9bb35c5d953b4108e63db9ee6b6069f2d' 
  AND token = '7N3krcRKDlNCldpFwpkcUEqnhqTBxfXSf5AwiTkMSd4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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