SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe2fd13c0fc97d5f93ea7856a2ef00aade9b78615118975e39b81d9b1090378c' 
  AND token = 'xSKkD7pLBqaucDaC2nkzWmXC62TjVO1sBGNebVT0B1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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