SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '7042238e9169609ebd28377e22fd6d685524d274838138c7230108aef6849023' 
  AND token = 'Wi+WdGO02NKhyxfCYaHpLxCwuU2JXiHOGHDDCCMEPAg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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