SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '46e03c1516a668e636e2e7d25c896d74db242a96de01b731e001884b19ddb103' 
  AND token = 'I8KIaf1BBw9tR/xNiHO1vGbzMCzAmjArFwrtwBsBOe4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}