SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '9c8fc1d602890219cbcfb6a7581b51d956690be64700a61e3b64be3b6448d783' 
  AND token = 'vCCyCgVEH9xQP44Oj8M3CmrlqWNFQuf+Q023ViXopIE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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