SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25856cceb6af695a0e5a75c6471947361ea25ff995db797843cda58454e908c3' 
  AND token = 'jG9pFmYJUSLbwBO7QlRGLjcowmsgd+DvyEAkCG38zI0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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