SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'ca373ff3342d7ac8f2afb490b5210f36d67909680f234dca4c673942c3e460a4' 
  AND token = 'qSzcS3i5HkPwNaExjq9/Tj/HMmQqhBwFJCWDbXjIsu4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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