SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '6b004188ac03efed01a232c84b6451c83964c1b55ea96f106dbff3f689503a2b' 
  AND token = 'T5lh86OlC8JIQpGarOtVBazgQhelf2lCfZ7WIhaIWB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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