SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b45a05ee4d9ebfe28396d944ae73f0bdc76ff66912fc7f57854e65f52c67102c' 
  AND token = 'GnotSsv7Q49VBJimIY8Iw7wyd5qM/NGslpJJHJ7mKC4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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