SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de83fe97aeb55d11866a9f785570935aa9308906e2dddee8f651710f41a374ff' 
  AND token = 'oGw4AExhLB+DeM7cMJZsUERWd7ryh6jmWpHwDk1FlB4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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