SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'fe03814fedafc9242928d12b6574c49992d5f1d98bf30806a745bf0e9aab3c77' 
  AND token = 'SiulhbutqkUsNuS8z099P9joWPKgbXGqMXSqC+yHwKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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