SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b552afddc2e91cd1c5bd7807af23f2f7065af148ede73cf28a9102a7fc1a6089' 
  AND token = 'dBxkx2pQ9J8mhDSbZ4437d5CQ7Ui6XCuCgv8SIwRMZQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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